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In systems and networks where overflow is penalized, careful planning is required to prevent a small increase in the offered load from suddenly triggering a system collapse. In this work, we consider an overflow loss system where the service time distribution of a request is dependent on the number of overflows. We propose a novel admission control policy for improving the stabilization and performance of such a system based on a new information exchange mechanism (IEM) for congestion information, in which only a small amount of congestion information is carried by each request and is propagated via the overflow of requests. This avoids the need for an external mechanism for propagating congestion information. Furthermore, IEM is fully compatible with trunk reservation, a simple, classical, yet effective method of admission control in overflow loss systems and networks. Despite the very limited amount of communication overhead required by IEM (only a few bits per request), numerical results demonstrate that the combination of IEM with trunk reservation provides greater performance and stability than trunk reservation alone. We also present a computationally efficient analytical performance evaluation method based on IEM and demonstrate numerically that it is asymptotically exact and generally quite accurate. Therefore, the analytical method can be used for system design and planning. |
